Voice over Long Term Evolution (VoLTE) is deployed using Internet Protocol Multimedia Subsystem (IMS) and customized Radio Access Network (RAN) features to enable voice services alongside other services that use high-speed data. IMS provides the interconnection/gateway functionalities that allow VoLTE devices to communicate with non-VoLTE devices or even non-wireless devices. Session Initiation Protocol (SIP) defines the signaling necessary for call establishment, tear-down, authentication, registration, and presence maintenance, as well as enabling supplementary services like three-way calling and call waiting.
For effective analysis and troubleshooting of a VoLTE session, engineers need to look into several interface messages and analyze performance indicators calculated based on messages and information elements pertaining to those messages. Engineers need to know how IMS is setting up the session, how intermediate protocols are setting up the required bearers, how the enhanced, or evolved, Node B (eNB) is channelizing the over air interface, what the effective Quality of Service (QoS) experienced by the user over the radio interface is, etc. This becomes more and more complex with multi-vendor network elements. So, in practice, VoLTE service testing, troubleshooting, and optimization on a live network is one of the biggest challenges experienced by service providers and vendors involved in design and optimization services.
Thus, there is a need for systems and methods for automated measurement and analysis of end-to-end performance of VoLTE service.